The triggering of B cell receptor complex (BCR) leads to activation of nuclear factor-KB(NF-KB)/REL family of transcription factors that is essential for survival and activation of normal B lymphocytes. Dysregulated NF-KB activation contributes to development and progression of B cell lymphoma and autoimmune diseases. The BCR NF-kB cascade is mediated via distinct "signalosomes" separated in cells in space and time and includes the BCR, CARMA1, IKK and NFkB multimolecular complexes. Multiple events can modulate specific localization, interaction and activation, or inhibition, of these signalosomes. While proteins with adaptor functions form a core for these complexes, multiple lines of investigation demonstrate crucial roles for protein and inositol kinases in this process. While it is now clear that Btk and PKCbeta play an essential role in immunoreceptor-induced NF-kB activation, the molecular events controlling this process remain to be fully defined. Among potential components of BCR-NF-kB cascade are members of the Protein Kinase D (PKD) family, a relatively recently recognized family of second-messenger-stimulated serine/threonine (Ser/Thr) protein kinases. Four lines of evidence suggest that PKD1/2 may participate in NFKB pathway: PKD is constitutively associated with Btk in B cells; PKDs are trans-phosphorylated by classic PKCs; PKD1 participates in NFKB pathway in epithelial cells via phosphorylation of IKKbeta; and the regulatory linker region of CARMA1 contains consensus PKD2 phosphorylation sites. Taking into account that majority of lymphocytes express PKD2 but not PKD1, the general objective of this proposal is to determine the role for PKD2 in modulation of BCR-Btk- PKCbeta mediated NFKB activation in B cells. In the current proposal, we will define molecular events that mediate Btk-dependent PKD2 activation. Further, we will test the hypotheses that PKCbeta is directly involved in the BCR dependent activation of PKD2. We will also address the question whether CARMA1 can serve as a direct substrate for PKD2. Finally, we will determine if the elevated PKCbeta expression and activation observed in diffuse large B cell lymphoma (DLBCL) cells correlates with alterations in PKD2 expression and activity. This will entail parallel studies of PKCB and PKD expression and activity in human DLBCL cell lines and samples obtained from patients with good prognosis (germinal center phenotype) vs. poor prognosis (activated B cell phenotype) disease. This Fogarty program based research work will be carried out primarily in the Ukraine at the R.E. Kavetsky Institute of Experimental Pathology, Oncology and Radiobiology National Academy of Sciences of Ukraine in collaboration with Svetlana Sidorenko as an extension of NIH Grant #4 R01 HD037091-07.